The Treasury Department on Monday identified Russia's second-largest financial institution, VTB Bank, as a key financial node for Iran's Islamic Republic and put further sanctions on the bank.

The new sanctions on VTB are a bid to pressure international partners to cut off dealings with it, according to people familiar with the matter. Treasury Secretary Scott Bessent has repeatedly threatened secondary sanctions against foreign companies that help Iran to evade U.S. economic restrictions.

Bessent, who announced a maximum pressure campaign against Iran dubbed Operation Economic Outcast last month, previewed the latest sanctions on Friday without naming the target. "We are just going to continue with this process until everyone stops dealing with this regime," he said.

VTB Bank didn't immediately return a request for comment.

The immediate impact of the new sanctions is unclear. VTB was already put under U.S. sanctions in 2022 in response to Russia's invasion of Ukraine, and the pre-existing sanctions prohibit any U.S. person or institution from dealing with VTB.

The Russian bank has continued to provide a major lifeline to Iran despite those sanctions, according to U.S. officials. VTB provides clearing accounts to the Central Bank of Iran and a number of sanctioned Iranian banks, allowing for the easy exchange of Iranian rials and Russian rubles, the people familiar with the matter said.

VTB has more than a thousand branches around the globe and a notable presence in India, the people said. It has moved to increase its presence in Iran and helped transfer billions in frozen Iranian assets, the Treasury said Monday.

The Treasury in recent weeks has inched toward more aggressively deploying its sanctions capabilities against Iran, including by moving to cut off banks in Turkey and the U.A.E that officials said help the regime evade sanctions.

Billions of dollars in Iran-related transactions move through U.S. banks each year thanks to a century-old network that allows banks in different countries to seamlessly exchange and transfer currencies. U.S. banks hold a special position in that system because of the importance of the U.S. dollar.

Cutting foreign banks off from the U.S. dollar accounts can hurt the dollar and have collateral consequences for U.S. allies and the global financial system more broadly, which has forced the Trump administration and its predecessors to move with caution when targeting adversaries such as Iran.

The Treasury last month moved to sever the Emirati branch of a state-owned Egyptian bank from its correspondent accounts at several large U.S. banks. The action stopped short of imposing full secondary sanctions on Banque Misr UAE.

So far, the Treasury Department hasn't targeted China, Iran's top trading partner, which has raised questions about how far it can go in squeezing the regime.

Miad Maleki, a senior Treasury official until last year, who now works at the Foundation for Defense of Democracies, said the move against VTB was likely also a warning to China. Maleki said that VTB's Shanghai branch is the only Russian bank inside China's payment system and it has become a key artery for Russian-Chinese trade.

By placing VTB under Iran sanctions, Treasury is telling Chinese banks that "their VTB business is now Iran business and, in this environment, Iran exposure is something no bank in Shanghai, Hong Kong or Mumbai wants on its books," he said.

China's leader Xi Jinping is due in Washington to meet President Trump this month.